Problem

The Auction:

You receive the ♥K lead against 4♠. Plan the play (trumps are 2-2).

Solution

A reasonable start would be to win the opening lead with the ace, play a spade to the queen and a spade to the ace, discovering that trumps are 2-2. A heart should be ruffed in dummy. Now, the contract can be guaranteed by playing a diamond to the ace, and playing a diamond back towards the jack. Here are the two possibilities:

West wins the trick with the ♦Q (or ♦K): If West cashes the ♦K, then dummy's jack will take care of a losing club. If West plays a small diamond, you will stick in the jack from dummy, which is likely to be won by East's king. This will mean that diamonds are 3-3, and you can discard one of your clubs on dummy's thirteenth diamond.

If West instead switches to a club, you should cover cheaply in dummy (i.e. if West plays a low club, you should play the eight, if West plays the jack or ten, you should cover with the queen). When East wins the trick, he will be endplayed. A club return will give up an immediate trick. If he cashes the ♦K, or plays a diamond to West's king, he will establish dummy's jack for a club discard.

East Wins the diamond: In this case, East can once again be endplayed. A club return is once again fatal. If East has four diamonds, and cashes top diamonds and tries to cash a fourth high diamond, you will discard a losing club from hand as dummy follows with a diamond, forcing East to play a club or concede a ruff and discard. Which brings us to another point - when you play the ♦A and a diamond, if West follows with the ten, you should cover with dummy's jack. It would be fatal to duck in dummy as West would then switch to a club.

Par Contract Analysis

On the actual lie of cards, the par contract is 5♠ by North-South. It should be noted that 11 tricks are possible only by double dummy lines.